Hydraulic unit for an anti-slip brake system

ABSTRACT

The present invention relates to a hydraulic unit whose ventilation system includes a pressure compensating channel ( 1 ) that extends transversely to the motor- and pump accommodating bore ( 2, 11 ) from the second housing surface (A 2 ) through the motor accommodating bore ( 2 ) in the direction of a third housing surface (A 3 ) in the accommodating member ( 3 ) positioned diametrically to the second housing surface (A 2 ).

TECHNICAL FIELD

The present invention relates to a hydraulic unit, in particular forslip-controlled brake systems.

BACKGROUND OF THE INVENTION

EP 0 787 084 B1 discloses a hydraulic unit of the indicated type whichincludes a ventilation system with one single ventilation point to theatmosphere aligned coaxially to the motor accommodating bore for thepurpose of central ventilation of the accommodating bores. To this end,the motor accommodating bore is configured as a through-bore in theaccommodating member. The rear portion of the accumulator accommodatingbore is ventilated by way of a complex channel system, comprised of atransverse channel and ventilation slots provided between the motorflange and the accommodating member and between the motor mountingsupport and the accommodating member.

As an alternative to this presented ventilation concept, anotherembodiment of EP 0 787 084 B1 discloses connecting the rear chamber ofthe accumulator accommodating bore directly to the hollow space in thehood which is in fluid-tight abutment on the first housing surface ofthe accommodating member. Pressure compensation takes place by way of aventilation point disposed in the hood. Leakage fluid of the pump is nothindered to propagate through the motor accommodating bore into thehood. Said hood accommodates electric and electronic components beingdisadvantageously exposed to moistening by fluid.

In view of the above, an object of the invention is to improve animmersion-proof hydraulic unit of the indicated type in such a fashionthat the ventilation system can be manufactured in a simplified way,with the aim of avoiding the above-mentioned shortcomings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the first housing surface of the hydraulic unit.

FIG. 2 is a side view of the accommodating member at the point ofintersection A—A known from FIG. 1.

FIG. 3 is another side view of the accommodating member at the point ofintersection B—B marked in FIG. 1.

FIG. 4 is a cross-section taken through the accommodating member in thearea of the pressure-balancing channel in the top view known from FIG.1.

FIG. 5 is an alternative design of a cover for closing two accumulatoraccommodating bores.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a hydraulic unit for slip-controlled brake systems in a topview of a block-shaped accommodating member 3 accommodating inlet andoutlet valves in several valve accommodating bores 8 of a first andsecond valve row X, Y, said valves opening into a first housing surfaceA1 of the accommodating member 3. Said first housing surface A1 isdisposed at right angles between a second and third housing surface A2,A3 which is limited by four lateral surfaces of the accommodating member3 in total, the edges of which surfaces can be easily seen in FIG. 1.Further, sections of a hood 7 that is attached to the first housingsurface A1 are sketched in the left-hand area of the accommodatingmember 3. Hood 7 is conformed to the contour of the accommodating member3 and covers several inlet and outlet valves inserted into the valveaccommodating bores 8. Electric controlling and/or regulating elementsare arranged in hood 7 and connected to the inlet and outlet valves andto an electric motor that is arranged at a housing surface of theaccommodating member 3 being positioned diametrically to the firsthousing surface A1.

Besides, FIG. 1 depicts a cable duct 9 between the two valve rows X, Yand, on top thereof, a pressure compensating channel 1 opening into thefirst housing surface A1. The vertical sectional planes A—A, B—B extendthrough the cable duct 9 and the pressure-compensating channel 1,illustrating hereinbelow by way of FIGS. 2, 3 the course of bores of theventilation system within the accommodating member 3 that is relevantfor the invention.

FIG. 2 discloses the design of the accommodating member 3 along thesectional plane A—A characterized in FIG. 1 and extending through thecable duct 9, the pressure compensating channel 1 and through the motoraccommodating bore 2 that points transversely to the direction the pumpaccommodating bore 11 opens into the accommodating member 3.

The invention arranges that the pressure compensating channel 1, as seenfrom the second housing surface A2, traverses the motor accommodatingbore 2 in the direction of the second housing surface A2 that ispositioned diametrically to the third housing surface A3 and bounds theaccommodating member 3. The pressure compensating channel 1 isconfigured as an angular channel and composed of a first and a secondblind-end bore pointing to the accommodating member 3 in a particularlysimple fashion, to what end the second blind-end bore forming a firstand a second pressure compensating channel portion 1 a, 1 b opens intothe second housing surface A2 and extends transversely through the motoraccommodating bore 2 up to the ventilation point 6 which is a part ofthe first blind-end bore. The first blind-end bore opens into the firsthousing surface A1 and intersects with its end the end of the secondblind-end bore to complete the angular channel. The ventilation point 6includes an element 10 that is permeable to gas, yet impermeable tofluid, and is preferably composed of a semi-permeable membrane.

It can be taken from FIG. 2 that the second pressure compensatingchannel portion 1 b extends between the motor accommodating bore 2 andthe ventilation point 6 which opens as a stepped bore into the firsthousing surface A1 of the accommodating member 3 directly at the end ofthe second pressure compensating channel portion 1 b. The secondpressure compensating channel portion 1 b traverses the cable duct 9,which is positioned in parallel to the valve accommodating bores 8 andarranged beside the motor accommodating bore 2. Cable duct 9 connectsthe electric motor inserted into the motor accommodating bore 2 toelectric controlling and/or regulating elements arranged beside thefirst housing surface A1, preferably in hood 7.

FIG. 3 shows a cross-section through the accommodating member 3 startingfrom the illustration of the sectional plane B—B in FIG. 1. Identicalwith the sectional plane A—A, the sectional plane B—B initially extendsalong the second pressure compensating channel portion 1 b up to themotor accommodating bore 2 and thereafter intersects the cross-sectionalarea of the accommodating member 3, in which the accumulatoraccommodating bore 4 is provided. The accumulator accommodating bore 4houses a spring-loaded piston whose spring is supported on the cover 5tightly closing the accumulator accommodating bore 4. Chamber 4 aconnected to the first pressure compensating channel portion 1 a isdisposed between the piston and the cover 5. Pressure compensation takesplace through chamber 4 a during the piston movement in the direction ofthe ventilation point 6, and pump leakage is accepted out of the motoraccommodating bore 2 through the first pressure compensating channelportion (1 a), to what end the absorptive volume of chamber 4 can bemodified in conformity with demand by respectively designing the cover5. Therefore, the cover 5 has a bowl-shaped design and includes aprojecting length Z at the second housing surface A2 in order toincrease the volume of leakage absorption.

FIG. 3 further shows the shaft portion of the electric motor necessaryfor the drive of the pump and substantially receiving the eccentricdrive inserted into the motor accommodating bore 2. The eccentric driveactuates the piston pump inserted into the pump accommodating bore 11.

Instead of the top view of the first housing surface A1 known from FIG.1, FIG. 4 shows a top view of a sectional surface which extends inapproximation along half the block length of the accommodating member 3and discloses the two valve rows X, Y with eight valve accommodatingbores 8 similar to FIG. 1, and the pump accommodating bore 11 arrangedexemplarily below the valve rows X, Y. The bore portion of bore 11forming the pump suction side is respectively connected through apressure fluid channel conducting the operating fluid to an accumulatoraccommodating bore 4 which adopts the function of a low pressureaccumulator supplying the pressure fluid coming from the outlet valvesto the pump. Two parallel arranged accumulator accommodating bores 4open into the second housing surface A2 at a radial distance from eachother. Within this radial distance, the pressure compensating channel 1extends centrically and thus mirror-symmetrically through theaccommodating member 3 from the second housing surface A2 to theventilation point 6. Both accumulator accommodating bores 4 are closedby one single trough-shaped cover 5.

The attachment of a one-part cover 5 for the tight closure of bothaccumulator accommodating bores 4 is equally shown in an enlarged viewof FIG. 5 on the basis of the illustration according to FIG. 4. Saidcover 5 is made by non-cutting metal shaping, preferably in deepdrawing,stamping or extruding operations. The pistons inserted into theaccumulator accommodating bores 4 are manufactured in the same way. Thepressure compensating channel 1 extends up to the cover 5 which, in thepresent example, has an additional indentation below the one accumulatoraccommodating bore within its trough contour. Any possible leakage ofthe pump can initially be admitted in the indentation. At its edge bentat right angles, cover 5 is attached by means of calking of the housingmaterial of the accommodating member 3. Of course, other equivalentattachment provisions by way of operative engagement and molecular bondare also possible.

Of course the accommodating member 3 also comprises several pressurefluid channels connecting the valve-, pump- andaccumulator-accommodating bores and permitting a hydraulic connectionbetween a pressure fluid generator and at least one pressure fluidreceiver. However, in order not to become confused, it is omitted toillustrate all pressure fluid channels in which the operating fluid isconveyed.

Rather, the description concentrates on the essential design innovationsfor configuring a ventilation system that allows ventilating and ventingthe pump accommodating bore 11 and the accumulator accommodating bore 4for pressure compensation to the atmosphere exclusively by way of onesingle ventilation point 6, to what end the invention focuses on thearrangement and construction of a pressure compensating channel 1, whichadditionally allows a storage of pump leakage in the area of theaccumulator accommodating bore 4.

Finally, it shall not be left unmentioned that, under the proviso ofsufficient space, the pressure compensating channel 1 is manufactured asthe only through-bore instead of a blind-end bore so that thethrough-channel 1 is made in a particularly simple drilling operation inconformity with the demands of automation to extend from the secondhousing surface A2 to the third housing surface A3, which includes theventilation point 6 with the fluid-impermeable element 10.

The invention is advantageous in that, upon request or requirement, onesingle element 10 can also be arranged in hood 7 so that the ventilationof the accumulator accommodating bores 4 and the pump- and motoraccommodating bores 11, 2 is carried out through the ventilation point 6arranged in the first housing surface A1 in the direction of thelarge-volume hollow space of the hood 7, which has a connection to theatmosphere through the element 10 especially when the hood 7 is sealedat the accommodating member 3.

1. Hydraulic unit for brake systems, comprising: an accommodating memberaccommodating inlet and outlet valves in several valve accommodatingbores of a first and second valve row, said valves opening into a firsthousing surface of the accommodating member that is disposed at rightangles between a second and third housing surface, a pump accommodatingbore arranged in the accommodating member and pointing transversely tothe direction the valve accommodating bores open into the accommodatingmember, a motor accommodating bore arranged in the accommodating memberfor driving a pump inserted into the pump accommodating bore, to whatend the motor accommodating bore is aligned transversely to the pumpaccommodating bore, at least one accumulator accommodating bore openinginto the accommodating member into the second housing surface, includinga ventilation system that permits ventilating and venting the pump- andaccumulator accommodating bore for pressure compensation exclusively byway of one single ventilation point that is in connection to a pressurecompensating channel of the ventilation system, the ventilation pointincluding an element that is permeable to gas, yet impermeable to fluid,wherein the pressure-compensating channel extends transversely to themotor- and pump accommodating bore from the second housing surfacethrough the motor accommodating bore in the direction of the thirdhousing surface in the accommodating member positioned diametrically tothe second housing surface.
 2. Hydraulic unit as claimed in claim 1,wherein a first pressure compensating channel portion extends betweenthe motor accommodating bore and a cover closing the accumulatoraccommodating bore and being attached to the second housing surface. 3.Hydraulic unit as claimed in claim 1, wherein a first pressurecompensating channel portion extends between the motor accommodatingbore and a cover closing the accumulator accommodating bore and beingattached to the second housing surface; or wherein two parallel arrangedaccumulator accommodating bores open into the second housing surface ata radial distance from each other in which the first pressurecompensating channel portion extends between the motor accommodatingbore and a cover closing the two accumulator accommodating bores. 4.Hydraulic unit as claimed in claim 2, wherein a discharge of pumpleakage from the motor accommodating bore to the accumulatoraccommodating bore is carried out through the first pressurecompensating channel portion into a chamber associated with theaccumulator accommodating bore, and an absorptive volume of said chamberis variable by way of a design of the cover; wherein a first pressurecompensating channel portion extends between the motor accommodatingbore and a cover closing the accumulator accommodating bore and beingattached to the second housing surface; and wherein two parallelarranged accumulator accommodating bores open into the second housingsurface at a radial distance from each other in which the first pressurecompensating channel portion extends from the motor accommodating boreup to the cover that closes the two accumulator accommodating bores. 5.Hydraulic unit as claimed in claim 4, wherein the cover has abowl-shaped design and includes a projecting length to increase theabsorptive volume of the chamber.
 6. Hydraulic unit as claimed in claim2, wherein the cover is made by non-cutting metal shaping.
 7. Hydraulicunit as claimed in claim 2, wherein the cover is made by deepdrawingplastic material.
 8. Hydraulic unit as claimed in claim 1, wherein asecond pressure compensating channel portion extends between the motoraccommodating bore and the ventilation point, which is fitted at an endof the second pressure compensating channel portion either directly inthe accommodating member or in a hood that is sealedly seated onto thefirst housing surface of the accommodating member.
 9. Hydraulic unit asclaimed in claim 8, wherein the hood covers several inlet and outletvalves inserted into the valve accommodating bores and connected toelectric controlling and/or regulating elements that are arranged in thehood.
 10. Hydraulic unit as claimed in claim 1, wherein the pressurecompensating channel is configured as an angular channel formed of afirst and a second blind-end bore, with the second blind-end borecomprised of two pressure compensating channel portions opening into thesecond housing surface and being led transversely through the motoraccommodating bore up to the ventilation point, and wherein the firstblind-end bore opens into the first housing surface and intersects thesecond blind-end bore.
 11. Hydraulic unit as claimed in claim 10,wherein one of the pressure compensating channel portions traverses acable duct which is positioned in parallel to the valve accommodatingbores and arranged beside the motor accommodating bore and connects anelectric motor inserted into the motor accommodating bore to electriccontrolling and/or regulating elements that are arranged beside thefirst housing surface.
 12. Hydraulic unit as claimed in claim 2, whereina first pressure compensating channel portion extends between the motoraccommodating bore and a cover closing the accumulator accommodatingbore and being attached to the second housing surface, preferably in anoperative engagement or a molecular bond; or wherein two parallelarranged accumulator accommodating bores open into the second housingsurface at a radial distance from each other in which the first pressurecompensating channel portion extends from the motor accommodating boreup to the cover that closes the two accumulator accommodating bores. 13.Hydraulic unit as claimed in claim 1, wherein a discharge of pumpleakage from the motor accommodating bore to the accumulatoraccommodating bore is carried out through a first pressure compensatingchannel portion into a chamber associated with the accumulatoraccommodating bore, and an absorptive volume of said chamber is variableby way of a design of the cover; wherein a first pressure compensatingchannel portion extends between the motor accommodating bore and a coverclosing the accumulator accommodating bore and being attached to thesecond housing surface, preferably in an operative engagement or amolecular bond; and wherein two parallel arranged accumulatoraccommodating bores open into the second housing surface at a radialdistance from each other in which the first pressure compensatingchannel portion extends from the motor accommodating bore up to thecover that closes the two accumulator accommodating bores.
 14. Hydraulicunit for brake systems, comprising: an accommodating memberaccommodating inlet and outlet valves in several valve accommodatingbores of a first and second valve row, said valves opening into a firsthousing surface of the accommodating member that is disposed at rightangles between a second and third housing surface, a pump accommodatingbore arranged in the accommodating member and pointing transversely tothe direction the valve accommodating bores open into the accommodatingmember, a motor accommodating bore arranged in the accommodating memberfor driving a pump inserted into the pump accommodating bore, to whatend the motor accommodating bore is aligned transversely to the pumpaccommodating bore, at least one accumulator accommodating bore openinginto the accommodating member into the second housing surface, severalpressure fluid channels that connect the valve-, pump- and accumulatoraccommodating bores and are adapted to provide a hydraulic connectionbetween a pressure fluid generator and at least one pressure fluidreceiver, including a ventilation system that permits ventilating andventing the pump- and accumulator accommodating bore for pressurecompensation exclusively by way of one single ventilation point that isin connection to a pressure compensating channel of the ventilationsystem, the ventilation point including an element that is permeable togas, yet impermeable to fluid, wherein the pressure-compensating channelextends transversely to the motor- and pump accommodating bores from thesecond housing surface through the motor accommodating bore in thedirection of the third housing surface in the accommodating memberpositioned diametrically to the second housing surface.
 15. Hydraulicunit as claimed in claim 14, wherein a first pressure compensatingchannel portion extends between the motor accommodating bore and a coverclosing the accumulator accommodating bore and being attached to thesecond housing surface.
 16. Hydraulic unit as claimed in claim 14,wherein a first pressure compensating channel portion extends betweenthe motor accommodating bore and a cover closing the accumulatoraccommodating bore and being attached to the second housing surface; orwherein two parallel arranged accumulator accommodating bores open intothe second housing surface at a radial distance from each other in whichthe first pressure compensating channel portion extends between themotor accommodating bore and a cover closing the two accumulatoraccommodating bores.
 17. Hydraulic unit as claimed in claim 15, whereina discharge of pump leakage from the motor accommodating bore to theaccumulator accommodating bore is carried out through the first pressurecompensating channel portion into a chamber associated with theaccumulator accommodating bore, and an absorptive volume of said chamberis variable by way of a design of the cover; wherein a first pressurecompensating channel portion extends between the motor accommodatingbore and a cover closing the accumulator accommodating bore and beingattached to the second housing surface; and wherein two parallelarranged accumulator accommodating bores open into the second housingsurface at a radial distance from each other in which the first pressurecompensating channel portion extends from the motor accommodating boreup to the cover that closes the two accumulator accommodating bores. 18.Hydraulic unit as claimed in claim 17, wherein the cover has abowl-shaped design and includes a projecting length to increase thevolume of the chamber.
 19. Hydraulic unit as claimed in claim 15,wherein the cover is made by non-cutting metal shaping.